There were successful organizing drives at vehicle assembly plants and suppliers, including the IC Bus plant in Tulsa, Okla., Flex-n-Gate in Arlington, Texas, and Faurecia in Louisville, Ky.

The UAW said it also organized thousands of new members in gaming at casinos in Ohio and Las Vegas.

Despite the growth in recent years, the UAW's membership trails its peak of 1.5 million members in 1979.

And the union, which is set on organizing the foreign automakers that populate the South, was dealt a harsh blow in February. That's when workers at the Volkswagen auto assembly plant in Chattanooga, Tenn., voted down the UAW bid's to organize them.

The UAW is appealing the election, citing outside interference from lawmakers and conservative special interest groups.

The union also has ongoing campaigns at Alabama's Mercedes-Benz plant and the Nissan plant in Canton, Miss.

“Workers in the South who are organizing are proving that Southern workers want and need unions," UAW President Bob King said in a prepared statement. "The UAW is going to continue to fight for their right to organize and we’re going to fight to protect our members across the county who face employer challenges and anti-union efforts to undermine collective bargaining rights."